My grocery store has started selling produce they would normally throw away. It's not rotten, it's just a little wilted or bruised.

All grocery store need to be doing that to decrease waste.

That’s an excellent idea. It all matters.

Don't laugh at people because you think you're superior to them (ie. know better). I don't find it surprising that people double-down when you think you're justified to laugh in their face. Causes more harm than good.

DO THIS: https://www.ncdc.noaa.gov/global-warming/last-1000-years

People will not change their minds because you tell them that they should. People change their minds by coming to different conclusions by themselves NOT by being ridiculed and belittled by some know-it-all.

Present that facts and resist the (possibly unintended) urge to antagonise. Listen to the points made and provide information if you wish to.

Boiling Frog.

The boiling frog is a fable describing a frog being slowly boiled alive. The premise is that if a frog is put suddenly into boiling water, it will jump out, but if the frog is put in tepid water which is then brought to a boil slowly, it will not perceive the danger and will be cooked to death. — Wikipedia